UT Arlington biologist helps map DNA code for the water flea

ARLINGTON - A UT Arlington biologist and her team have
helped precisely map the DNA code of the water flea, Daphnia pulex, the first crustacean genome to be sequenced.

Ellen Pritham

Daphnia emerges as a model organism for a new field – environmental genomics. Researchers in the field aim to better understand how genes and the environment interact. Their
work includes building research tools for investigating
the molecular underpinnings of key ecological and evolutionary problems.

Ellen Pritham, assistant biology
professor at The University of Texas at Arlington, said the
genome holds some big surprises. More genes were found in the Daphnia pulex genome than any other
animal ever sequenced. The Daphnia genome has about 31,000 genes compared to
about 20,000 in humans.

Pritham’s work with an international team
is reported this month’s edition of Science magazine
in an article called “The Ecoresponsive Genome of Daphnia pulex.”
Researchers hypothesized that many of the new genes are involved in Daphnia’s intimate relationship with its
environment and allow the organism to respond to a changing environment.

“The genome is the recipe book for
building an organism,” Pritham said. “Decoding the genome of a species is the
first step to understanding what it takes to build that species and to see what
components are the same and which are different… Interestingly, despite Daphnia
being more closely related to insects, it shares more genes in common with
humans.”

Pritham’s lab was part of the
transposable element annotation team. Transposable elements are genomic
parasites. They are mobile pieces of DNA in the genome that do no benefit to
the organism.

“The organism can't get rid of them,”
Pritham said. “Transposable elements frequently make up the largest proportion
of an organism's genome. Therefore, once a genome has been sequenced it is
critical that the transposable elements are annotated. The precise mapping of
the transposable elements allows the genes to be annotated properly.”

Pamela Jansma, dean of UT Arlington’s College of Science, described
Pritham’s work as groundbreaking.

“It exemplifies the type of research
that we do in the College of Science,” Jansma said. “Exciting discoveries occur
at the boundaries of disciplines where new fields, such as environmental
genomics, are created. Understanding how organisms evolve and adapt to
environmental change is a fundamental challenge.”

Pritham’s work is representative of the cutting-edge
discoveries taking place at The University of Texas at Arlington, a
comprehensive research institution of nearly 33,000 students in the heart of
North Texas. Visit www.uta.edu to learn
more.